From Salting To Fermentation: The Art of Fish Preservation
Image Credit: Canva

Fishing communities, among the world's oldest, have coexisted with the sea for centuries, relying on it for daily needs. Coastal and inland fishing communities have historically thrived along water bodies, including rivers and seas, contributing to the rise of great civilizations. In India, the sea has played a pivotal role in the livelihoods of coastal fishing communities.

They live close to the sea, ensuring easy access for daily necessities, from berthing boats to processing and marketing catches. Fish and seafood, rich in protein, form a significant part of their diet, and fishing income sustains their other needs.

Preserving fish for off-seasonal consumption is an age-old traditional practice followed by people in Asia, especially in South and Southeast Asia. There are various ways to cure and preserve fish and seafood, and there are equally unique ways to prepare them into various dishes. Salt-curing, sun-drying, pickling, fermenting, and smoking are some of the methods that have been followed in India.

The Preserved Fish Is Worth Its Salt

While fishing is an age-old practise, fish and seafood are highly perishable commodities that need to be carefully cured before anything else. You might have noticed that the moment fish is brought home, it is commonly treated with salt. It is a magical way to keep fish fresh for a long time without using a fridge. 

Fish usually have a lot of water in them, around 75–80%. When we salt it, some of that water turns into a salty mixture, and about 6–10% salt is created inside the fish. It's like a shield that protects the fish from going bad. Fish can be salted in various ways: through brining (a salt and water mixture), wet-salting, or dry-salting. It's important to maintain hygienic conditions during the salting process to prevent food safety issues. 

According to research by the Central Marine Fisheries Research Institute on the Research Gate website, salting induces osmosis, drawing water out of fish cells and into the surrounding salt solution. This process lowers the water content in fish, inhibiting biochemical reactions and microbial growth. The addition of salt is a critical step in preserving fish across the world. The fish is mostly cured in salt before sun-drying, canning, or fermenting.

The UN's Food And Agriculture Organisation states that you should use food-grade salt that's clean and pure. Some salts have extra minerals in them, like calcium sulphate and magnesium sulphate, especially the ones from the sea, which can make them spoil or taste funny. Also, think about the size of the salt crystals. If they're too tiny, they might stick together and not spread evenly on the fish. But if they're super big, they could bruise the fish while it's getting salted.

In Kerala, salt-dried fish is used for making a simple fry with coconut oil, a roast with pepper, curry leaves, and onions, or a ball of chutney called chammanthi with coconut, ginger-garlic, and birds-eye chillies.

The Demand For Dried Fish Goes Up During Monsoon

Sun drying is a cost-effective method that reduces fish moisture content, hindering microbial growth. It prevents spoilage caused by enzymes, microbes, and chemical reactions. By reducing water activity, it makes the environment less conducive for microorganisms to thrive.

During the monsoon, a season when sea fishing is restricted due to breeding concerns, the demand for salt-dried or sun-dried seafood surges among Indian coastal communities, especially in Goa and Kerala. For these communities, whose daily diet heavily relies on fish and seafood, this preserved delicacy becomes a culinary lifeline.

As you wander through coastal towns along the eastern and western shores of India, in states like Kerala, Karnataka, Tamil Nadu, Andhra Pradesh, West Bengal, Orissa, and beyond, you'll encounter quaint shops showcasing an array of salt-dried fish and seafood. These delectable treats endure the challenges of humidity and varying weather conditions in these regions.

While dried shrimps, mackerel, sardines, and silver fish are the expected finds, you'll be pleasantly surprised to discover an eclectic lineup featuring salt-dried pomfret, lizard fish, angel fish, ribbon fish, prawns, shark fish, Bombil, tuna, and sole fish, all adding their unique flavours to this coastal feast.

A dry fish, or dry prawn kismur, is a traditional delicacy without which a Goan meal is incomplete, especially during the monsoons. It is an accompaniment that includes various kinds of dried fish or prawns that are roasted and sauteed with grated coconut, red chilli powder, green chillies, onions, and a dash of kokum juice or lemon drops.

The tiny freshwater fish like ayirai or koilee meen that are available in plenty during the monsoon are later sun-dried and preserved for usage throughout the year until the next harvest. The dried koile meen is used to make pickles or is simply fried in coconut oil with spices in Kodagu to accompany simple meals like boiled rice and curries or rice porridge called kanji.

In Tamil Nadu, dried fish is called uppu karuvaadu, and the fish is salted and dried to preserve its nutrients for a long time. "When we buy karuvaadu from the shop, my mother applies turmeric and salt to it and wraps it up in a paper towel or newspaper before storing it in airtight containers, which ensures that the fish won't spoil for six to eight months," says Rajan, a software engineer from Triplicane in Chennai.

He continues to say, "We make a dish called manja thanni, which is like a fish rasam, and we use dried fish sometimes to make this dish that goes well with steamed rice. During the COVID lockdown months in 2020, dried fish, or karuvadu poriyal and fry, became a staple in our household as access to fresh fish was limited or not possible." 

Dried anchovies or Nethili fish are used to make thokku or curries with brinjal and tomatoes in Andhra Pradesh. While freshwater fish from the river Godavari and saltwater fish from the sea towards Vishakapatnam are available in plenty, sun-drying of fish takes place in large quantities in this state, which also gets exported commercially to other countries.

The people in West Bengal are big on salt-curing and sun-drying fish, which is called shutki maach. A Bengali hot garlic dry fish chutney called shutki maach bata is a popular preparation that is savoured with rice. It is a pungent dish that may be acquired by many.

"Having been sent off to the hostel for studies very young, I would look forward to the spicy hot shutki maach bata made by my mother with dried Bombay duck fish. Having grown up eating this piquant relish, it is my comfort food," says Madhumita DasGupta, a retired teacher and home cook in Bengaluru.

She adds by further saying, "Having moved to Bengaluru about 25 years ago, I had to think twice back then to prepare this dish as it exuded a pungent odour that the vegetarian neighbours didn't like. After moving places and into our own house 10 years ago, I can make it once in a while and indulge in it completely. This recipe was passed on to me by my mother, and I have passed it on to my son, who relishes the dish as much as I do, while my daughter can't stand the strong aromas of the shutki maach bata."

Fish In A Pickle

Fish pickle-making is an intricate process that requires precision to avoid spoilage. It's a spicy and flavourful condiment prepared with fish, vinegar, and various spices. Different types of fish, including tuna, seer fish, butterfish, prawns, anchovies, pomfret, sardine, and more, can be used based on regional preferences and availability. Prawns and shrimp can also be used to make pickles. The process of pickling allows you to use fresh fish and prawns to make pickles that can be stored for a couple of months without having to worry about them spoiling.

In Kerala, they're known for "meen achar," made with spices like mustard seeds, red chilli powder, turmeric, curry leaves, and asafoetida, along with vinegar and good-quality cooking oil like sesame or mustard oil, which have a prolonged shelf life and enhance the flavour and texture of the pickles. Salt is essential for both flavour and preservation. 

In coastal Karnataka, fresh fish is cleaned and cooked with dry masala that includes red chillies, black pepper, turmeric, fenugreek seeds, garlic, and souring agents like tamarind, kokum, or vinegar, which is reduced until moisture evaporates. After cooling, they're stored in glass jars and covered in a dry place. This careful process ensures delicious and long-lasting fish pickles.

"I grew up in a large household that would feed about 40 people for every meal. Once every six months, we would get fresh catch and spend half a day cleaning about 10–15 kilos of fish for pickling. My mother and sisters would cook them, pickle them, and transfer them to large ceramic jars. A layer of seasoned oil was added atop to coat the pickle in the jar from the top to enhance its shelf life. Every week, a batch of this pickle would be removed into a smaller jar that was used to serve for lunch and dinner along with steamed rice and a runny curry or just on its own," says Jayaprakash Hegde, an agriculturist from Agumbe in Karnataka.

Fermenting Fish Is A Traditional Technique Of Preservation

This way of preserving fish played a crucial role before modern techniques like refrigeration and canning emerged. Fish is highly perishable and prone to spoilage due to bacterial activity, making preservation essential. Fermentation effectively halts bacterial growth by increasing the fish's acidity, typically to a pH below 4.5.

Fermented fish preparations are popular in the north-eastern regions of India and are known for their pungent odour. In some parts, the fish, after gutting and washing them, are combined with dried fruit pulp or tamarind, salted, and then placed in brine, ensuring they remain submerged using weighted mats. This mixture is left to ferment for a duration ranging from 2 to 4 months before it is used for cooking.

In Meghalaya, fish is fermented to make tungtap, a tribal delicacy, in a traditional manner. The cleaned fish is dried for 2–4 days. They are then mixed with fish fats and salt and transferred to an earthen pot, which is sealed with rice paste, covered with slamet leaves, and stored away for 4-6 months before it is used to make tungtap.

Napham is a fermented fish-based dish primarily crafted by the Bodo tribe. This culinary delight is prepared using dried fish, tender arum shoots, mature Bambusa balcoa stem cylinders, clay paste, and straw. Small fish undergo gutting, cleaning, and sun-drying for about 2 hours to remove all moisture. Subsequently, they are smoked over a low flame using rice chaff until completely dried.

The dried fish is then ground, traditionally incorporating arum stems and chilli for good luck, using a mortar and pestle called "uwal" and "gaihen" in the local Bodo dialect. This mixture is packed into a hollow bamboo container, sealed with clay and straw to create anaerobic conditions, and left to ferment for 2–3 months. Napham is cherished for its flavour, nutrition, and long-lasting preservation, serving as a culinary staple during times of fish scarcity along with rice.

Nakham is a fermented fish product made by the Garo community, indigenous to Meghalaya and Kokrajhar. Unlike Napham, Nakham uses khar instead of Colocasia stem. The mixture ferments for 1 week to 1 month inside bamboo or jars, per Garo tradition.